I thought I'd chime in here. I have used the oculus rift cv1 for about 6 months now in Elite, and yesterday I tried the pimax 4k. I have 2 systems this was tested on. First is my main system, i7 4790k, 32gb ram, gtx 1080, windows 10 pro. Second was an i5 4690, 16gb ram, and a gtx 980ti. I also had a friend here, just so we can try two different perspectives because hey, everyone's head is shaped different. We both had the same conclusions:
While yes, there is very little to no screen door effect, (which is why I tried so hard to get this working well) the colors are super washed out. Turning your head quickly has horrible ghosting. Also, you can't focus on anything far away. (I've had my IPD measured at the eye doctor very recently, so the settings on both the cv1 and the pimax are perfect meaning that's not a concern.) Framerates are decent, not great, but they are acceptable. Here's how I can best describe it:
With the Oculus rift, (or the Vive, i've used it as well although not on this particular system so left it out of the comparison) I feel like I'm actually in the ship.
With the PiiMax 4k, I feel like i have a screen wrapped around my head. Depth perception is terrible, and again, washed out colors and a much worse display make it just unusable for me.
I can not see how anyone who's used either a vive or oculus in this game could possibly downgrade this much. (Yes, no god rays either forgot to mention.)
I also did this on 2 seperate windows installations, one was completely clean (win 10) just to make sure there were no left over drivers/reg entries from the rift causing problems.
I fell for the hype, and thankfully i got it on amazon it's getting returned today. (I even tried to see if I could use it for virtual desktop, or movies, and even that I just couldn't deal with. I'll take a little screen door effect for a screen that doesn't look like a first gen lcd screen on a smartphone. Resolution, sadly, isn't everything.
And the software, OH GOD the software. I've never seen a bigger mess in my life. Buggy drivers, horrid interface, absolutely no documention that's not garbage from their support forums trying to convince people that their "kickstarter doesn't suck", anyone with a decent system, and the cash for a different vr solution should steer FAR away from this. (Keep in mind, I've been an IT engineer for almost 18 years now, so I do know my way around. I spent 12 hours tweaking, testing, doing everything possible to make this work because i do really want a display with no god rays and no sde.)
Final thoughts, stay away. Although this gives me great hope for the next generation of devices with higher res screens. They're just not ready for primetime yet. (I still love the oculus and am not regretting the purchase. This is also not an attempt to validate my purchases, as I was perfectly willing to keep both and use them for different situations.)
Just my 2 cents.